JP7021619B2 - Transformers and power converters - Google Patents

Description

The present disclosure relates to transformers and power converters.

It is known to increase the leakage inductance of a transformer in order to improve the power conversion performance of the transformer. Leakage inductance is caused by the magnetic flux that intersects only one of the primary and secondary windings of the transformer. In order to generate such a magnetic flux, conventionally, for example, as disclosed in Patent Documents 1 and 2, in addition to the main core, a bypass core which is a magnetic path for guiding the magnetic flux leaked from the main core is provided. Transformers are known.

In Patent Document 1, an electrically insulated magnetic material gap piece is inserted between the primary winding and the secondary winding of the transformer, and the winding is cooled by the gap piece, and the leakage flux between the windings is measured. A power transformer having an inductance effect due to an increase is disclosed.

Patent Document 2 discloses a leakage flux type transformer including a main core, a first winding, a second winding, and one or more path cores. The main core is a first magnetic material that forms a closed magnetic path and has an outer leg and a middle leg. The first winding is wound so as to surround the middle foot with the longitudinal direction of the middle foot as an axis. The second winding is wound so as to surround the first winding with the longitudinal direction of the midfoot as an axis. The path core is a second magnetic material that penetrates a part of the region from the innermost circumference of the first winding to the outermost circumference of the second winding along the axial direction, and both of the second magnetic materials. The second magnetic material extends to a position where the magnetic flux passing through the inside of the first winding of the magnetic flux leaking from each end is equal to or less than the threshold value.

Japanese Unexamined Patent Publication No. 53-024530 Japanese Unexamined Patent Publication No. 2016-219540

In a power conversion device equipped with a transformer, characteristics such as gain change depending on the excitation inductance and the leakage inductance. In order to satisfy the desired circuit constant while achieving a high power density, it is necessary to adjust the excitation inductance while achieving a large leakage inductance. The exciting inductance is adjusted by providing a gap in the core. However, if a gap is provided in the core, leakage flux is generated. Loss occurs when this leakage flux intersects the winding. Therefore, there is a demand for a transformer that can adjust the exciting inductance without increasing the loss and has a large leakage inductance.

An object of the present disclosure is to provide a transformer capable of adjusting the excitation inductance and increasing the leakage inductance without increasing the loss. It is also an object of the present disclosure to provide a power converter with such a transformer.

The transformer and the power conversion device according to the aspect of the present disclosure have the following configurations in order to solve the above-mentioned problems.

The transformer according to one aspect of this disclosure is
The main core with the shape of a loop and
With the first winding wound around the main core in the first section of the loop of the main core,
A second winding wound around the main core in a second section of the loop of the main core away from the first section,
With at least one first bypass core provided along the first section of the main core and outside the first winding.
A third winding wound around the main core and the first bypass core in the first section of the main core.
With at least one second bypass core provided along the second section of the main core and outside the second winding.
A fourth winding wound around the main core and the second bypass core in the second section of the main core.
It comprises at least one gap formed in the main core so as to intersect the loop of the main core at a position away from both the first and second sections of the main core.

Here, the "first winding" and the "second winding" are used as the primary winding of the transformer, and the "third winding" and the "fourth winding" are the secondary windings of the transformer. It may be used as a winding. As an alternative, the "first winding" and "second winding" are used as the secondary winding of the transformer, and the "third winding" and "fourth winding" are the primary winding of the transformer. It may be used as a winding.

According to the transformer according to one aspect of the present disclosure, by providing the bypass core, a magnetic flux returning from the main core to the main core via the bypass core (that is, a magnetic flux passing through the bypass core) is generated. The magnetic flux passing through the bypass core does not intersect the third and fourth windings, but only the first and second windings. By generating the magnetic flux passing through the bypass core, a large leakage inductance can be generated. Further, according to the transformer according to one aspect of the present disclosure, the leakage magnetic flux intersects the winding by generating the leakage magnetic flux in the gap formed at a position away from the first to fourth windings. The exciting inductance can be adjusted while preventing the increase in loss due to the leakage flux crossing the winding. As described above, according to the transformer according to one aspect of the present disclosure, the leakage inductance can be increased without increasing the loss.

In the transformer according to one aspect of the present disclosure,
The first bypass core extends over a length that exceeds the length of the first section.
The second bypass core may extend over a length that exceeds the length of the second section.

According to a transformer according to one aspect of the present disclosure, the amount of magnetic flux passing through the bypass core varies depending on the length of the first and second bypass cores, and thus the leakage inductance generated by the magnetic flux passing through the bypass core. Can be changed.

In the transformer according to one aspect of the present disclosure,
The first and second bypass cores may extend along the main core and bend towards or along the main core at both ends.

According to the transformer according to one aspect of the present disclosure, by bending both ends of the first and second bypass cores, the amount of magnetic flux passing through the bypass core is increased as compared with the case where the bypass cores are not bent at both ends. It can be increased and thus the leakage inductance caused by the magnetic flux passing through the bypass core.

The transformer according to one aspect of this disclosure is
A plurality of first bypass cores and a plurality of second bypass cores may be provided.

According to the transformer according to one aspect of the present disclosure, the amount of magnetic flux passing through the bypass core is increased as compared with the case where one first bypass core and one second bypass core are provided, and thus the bypass core is provided. The leakage inductance caused by the passing magnetic flux can be increased.

In the transformer according to one aspect of the present disclosure,
The first and third windings are wound so as to be in contact with the surface of the main core and alternately arranged on the surface of the main core every turn.
The second and fourth windings may be wound so as to be in contact with the surface of the main core and alternately arranged on the surface of the main core every turn.

According to the transformer according to one aspect of the present disclosure, by winding the primary winding and the secondary winding so as to be alternately arranged on the surface of the main core, the winding is performed as compared with the case where the primary winding and the secondary winding are not wound in this way. The loss due to the proximity effect of the windings can be reduced.

The transformer according to one aspect of this disclosure is
In the third section between one end of the first section and one end of the second section of the loop of the main core, the main core is formed so as to intersect the loop of the main core. With at least one gap,
Formed on the main core so as to intersect the loop of the main core in the fourth section between the other end of the first section and the other end of the second section of the loop of the main core. It may be provided with at least one gap.

According to the transformer according to one aspect of the present disclosure, the leakage flux intersects the winding by generating the leakage flux in the gap formed at a position away from the first to fourth windings. The excitation inductance can be adjusted while preventing the increase in loss.

The transformer according to one aspect of this disclosure is
At least one of the third and fourth sections may include a plurality of gaps formed in the main core so as to intersect the loop of the main core.

According to the transformer according to one aspect of the present disclosure, by increasing the number of gaps, the leakage range of the leakage flux becomes smaller and it becomes difficult to cross the winding.

The transformer according to one aspect of this disclosure is
The transformer has first to fourth terminals and has
The first and second windings exert a magnetic flux in the same direction along the loop of the main core by the first and second windings when a current flows between the first and second terminals. Connected in series between the first and second terminals so as to occur
The third and fourth windings exert a magnetic flux in the same direction along the loop of the main core by the third and fourth windings when a current flows between the third and fourth terminals. As it occurs, it may be connected in series between the third and fourth terminals.

According to the transformer according to one aspect of the present disclosure, an input current may be supplied to the first and second terminals, and an output current may be generated from the third and fourth terminals. Further, according to the transformer according to one aspect of the present disclosure, an input current may be supplied to the third and fourth terminals, and an output current may be generated from the first and second terminals.

The transformer according to one aspect of this disclosure is
The transformer has first to fifth terminals and has
The first and second windings exert a magnetic flux in the same direction along the loop of the main core by the first and second windings when a current flows between the first and second terminals. Connected in series between the first and second terminals so as to occur
The third winding is connected between the third and fifth terminals.
The fourth winding is connected between the fourth and fifth terminals.
The third and fourth windings are along the loop of the main core by the third and fourth windings as current flows from the fifth terminal to the third and fourth terminals, respectively. They may be connected to each other to generate magnetic fluxes in the same direction.

According to the transformer according to one aspect of the present disclosure, the input current is supplied to the first and second terminals, the first output current is generated from the third and fifth terminals, and the fourth and fifth terminals are generated. A second output current may be generated from the terminal.

The transformer according to one aspect of this disclosure is
The transformer has first to fifth terminals and has
The first winding is connected between the first and fifth terminals.
The second winding is connected between the second and fifth terminals.
The first and second windings are along the loop of the main core by the first and second windings as current flows from the fifth terminal to the first and second terminals, respectively. Connected to each other to generate magnetic flux in the same direction,
The third and fourth windings exert a magnetic flux in the same direction along the loop of the main core by the third and fourth windings when a current flows between the third and fourth terminals. As it occurs, it may be connected in series between the third and fourth terminals.

According to the transformer according to one aspect of the present disclosure, the input current is supplied to the third and fourth terminals, the first output current is generated from the first and fifth terminals, and the second and fifth terminals are generated. A second output current may be generated from the terminal.

The power conversion device according to one aspect of the present disclosure includes a transformer according to each aspect of the present disclosure.

According to the power conversion device according to one aspect of the present disclosure, the leakage inductance of the transformer can be increased without increasing the loss of the transformer. This makes it possible to increase the gain of the power converter and increase its power density.

According to the transformer according to one aspect of the present disclosure, the exciting inductance can be adjusted and the leakage inductance can be increased without increasing the loss.

It is a front view which schematically exemplifies an example of the structure of the transformer 10 which concerns on 1st Embodiment. It is a top view which schematically exemplifies an example of the structure of the transformer 10 of FIG. It is sectional drawing which schematically exemplifies an example of the magnetic flux generated in the transformer 10 of FIG. It is a front view which schematically exemplifies an example of the structure of the transformer 100 which concerns on a comparative example. It is a graph which schematically exemplifies an example of the operation of the transformer provided with windings 103, 104 which concerns on a comparative example. It is a graph which schematically exemplifies an example of the operation of the transformer 10 of FIG. It is a figure which schematically exemplifies an example of the connection of windings 3a to 4b in the transformer 10 of FIG. It is a circuit diagram which schematically exemplifies an example of the part of the power conversion apparatus provided with the transformer 10 of FIG. 7. It is a figure which schematically exemplifies another example of the connection of windings 3a to 4b in the transformer 10 of FIG. It is a circuit diagram which schematically exemplifies an example of the part of the power conversion apparatus provided with the transformer 10 of FIG. It is a figure which schematically exemplifies another example of the connection of windings 3a to 4b in the transformer 10 of FIG. It is a circuit diagram which schematically exemplifies an example of the part of the power conversion apparatus provided with the transformer 10 of FIG. It is a front view which schematically exemplifies an example of the structure of the transformer 10A which concerns on the 1st modification of 1st Embodiment. It is a front view which schematically exemplifies an example of the structure of the transformer 10B which concerns on the 2nd modification of 1st Embodiment. It is a front view which schematically exemplifies an example of the structure of the transformer 10C which concerns on the 3rd modification of 1st Embodiment. It is a front view which schematically exemplifies an example of the structure of the transformer 10D which concerns on the 4th modification of 1st Embodiment. It is a side view which schematically exemplifies an example of the structure of the transformer 10E which concerns on the 5th modification of 1st Embodiment. It is a top view which schematically exemplifies an example of the structure of the transformer 10E of FIG. It is a front view which schematically exemplifies an example of the structure of the transformer 10F which concerns on the 6th modification of 1st Embodiment. It is a front view which schematically exemplifies an example of the structure of the transformer 10G which concerns on the 7th modification of 1st Embodiment. It is a side view which schematically exemplifies an example of the structure of the transformer 10H which concerns on the 8th modification of 1st Embodiment. FIG. 3 is a top view schematically illustrating an example of the configuration of the transformer 10H of FIG. 21. It is a circuit diagram which schematically exemplifies an example of the power conversion apparatus which concerns on 2nd Embodiment. It is a graph which schematically exemplifies an example of the operation of the resonance circuit of the power conversion device of FIG. 23.

Hereinafter, an embodiment according to one aspect of the present disclosure (hereinafter, also referred to as “the present embodiment”) will be described with reference to the drawings. In each drawing, the same reference numerals indicate similar components.

[First Embodiment]
The transformer according to the first embodiment will be described with reference to FIGS. 1 to 22.

[Structure example of the first embodiment]
FIG. 1 is a front view schematically illustrating an example of the configuration of the transformer 10 according to the first embodiment. The transformer 10 includes a main core 1, at least one bypass core 2a, at least one bypass core 2b, windings 3a, 3b, 4a, 4b, and at least one gap G.

The main core 1 includes a plurality of main core portions 1a and 1b. The plurality of main core portions 1a and 1b are made of a magnetic material such as ferrite. The main core portions 1a and 1b are formed in a U shape, for example. The plurality of main core portions 1a and 1b are mechanically connected to each other via, for example, a spacer 5 so as to form at least one gap G of a predetermined distance B1 between them. The main core 1 has a loop shape as a whole.

In the example of FIG. 1, sections A1 to A4 are provided along the loop of the main core 1. Here, the sections A1 and A2 each have a predetermined length B3 and are provided at positions separated from each other. The section A3 is provided between one end of the section A1 and one end of the section A2. The section A4 is provided between the other end of the section A1 and the other end of the section A2.

In the present specification, the sections A1 to A4 are also referred to as "first section", "second section", "third section", and "fourth section", respectively.

The winding 3a is wound around the main core 1 (in the example of FIG. 1, the main core portion 1a) in the section A1 of the loop of the main core 1. The winding 3a is provided with ends T1 and T2 at both ends thereof. The winding 3b is wound around the main core 1 (in the example of FIG. 1, the main core portion 1b) in the section A2 away from the section A1 in the loop of the main core 1. The winding 3b is provided with ends T3 and T4 at both ends thereof.

In the present specification, the winding 3a is also referred to as a "first winding", and the winding 3b is also referred to as a "second winding".

The bypass core 2a is provided along the section A1 of the main core 1 and outside the winding 3a. The bypass core 2b is provided along the section A2 of the main core 1 and outside the winding 3b. The bypass cores 2a and 2b are made of a magnetic material such as ferrite, for example. In the example of FIG. 1, the bypass cores 2a and 2b are formed linearly. The bypass cores 2a and 2b are mechanically connected to the main core 1 with a predetermined distance B2, for example, via a spacer 6. In the example of FIG. 1, the bypass core 2a is mechanically connected to the main core portion 1a, and the bypass core 2b is mechanically connected to the main core portion 1b.

The bypass core 2a extends over a length B4 that exceeds the length B3 of the section A1. The bypass core 2b extends over a length B4 that exceeds the length B3 of the section A2.

In the present specification, the bypass core 2a is also referred to as a "first bypass core", and the bypass core 2b is also referred to as a "second bypass core".

The winding 4a is wound around the main core 1 (main core portion 1a in the example of FIG. 1) and the bypass core 2a in the section A1 of the main core 1. The winding 4a is provided with ends T5 and T6 at both ends thereof. The winding 4b is wound around the main core 1 (main core portion 1b in the example of FIG. 1) and the bypass core 2b in the section A2 of the main core 1. The winding 4b is provided with ends T7 and T8 at both ends thereof.

In the present specification, the winding 4a is also referred to as a "third winding", and the winding 4b is also referred to as a "fourth winding".

The windings 3a and 4a are wound so as to be in contact with the surface of the main core 1 and alternately arranged on the surface of the main core 1 every turn. The windings 3b and 4b are wound so as to be in contact with the surface of the main core 1 and alternately arranged on the surface of the main core 1 every turn.

The gap G is formed in the main core 1 so as to intersect the loop of the main core 1 at a position away from both the sections A1 and A2 of the main core 1. In the example of FIG. 1, the transformer 10 includes one gap G formed in the section A3 and one gap G formed in the section A4.

As will be described later with reference to FIGS. 7 to 12, the windings 3a and 3b may be used as the primary winding and the windings 4a and 4b may be used as the secondary winding. Further, the windings 4a and 4b may be used as the primary winding and the windings 3a and 3b may be used as the secondary winding.

The plurality of main core portions 1a and 1b may be mechanically connected to each other by using other connecting means such as a support frame or a resin mold instead of the spacer 5. The bypass cores 2a and 2b may be mechanically connected to the main core 1 by using other connecting means such as a support frame or a resin mold instead of the spacer 6. In each drawing other than FIG. 1, spacers 5 and 6 (or other connecting means) are omitted for simplification of illustration.

FIG. 2 is a top view schematically illustrating an example of the configuration of the transformer 10 of FIG. As described above, the winding 3a is wound around the main core portion 1a, the winding 3b is wound around the main core portion 1b, and the winding 4a is wound around the main core portion 1a and the bypass core 2a. 4b is wound around the main core portion 1b and the bypass core 2b. In FIG. 2, for the sake of explanation, the winding 4a is shown on the outside of the winding 3a, but the windings 3a and 4a are respectively wound so as to be in contact with the surface of the main core 1 as described above. Similarly, in FIG. 2, for the sake of explanation, the winding 4b is shown on the outside of the winding 3b, but the windings 3b and 4b are respectively wound so as to be in contact with the surface of the main core 1 as described above. ..

[Operation example of the first embodiment]
FIG. 3 is a cross-sectional view schematically illustrating an example of the magnetic flux generated in the transformer 10 of FIG. The arrows shown above the main core 1 and the bypass cores 2a and 2b indicate the magnetic flux. When a current is passed through the windings 3a, 3b or 4a, 4b, as shown in FIG. 3, a magnetic flux is generated along the loop of the main core 1, and a leakage flux is generated in the gap G. The larger the distance B1 of the gap G (see FIG. 1), the larger the leakage flux. As mentioned above, loss occurs when the leakage flux intersects the winding. In the transformer 10 according to the present embodiment, since the gap G is formed at a position away from the windings 3a to 4b, it is possible to prevent the leakage flux generated in the gap G from crossing the windings 3a to 4b, and therefore, It is possible to prevent an increase in loss due to the leakage flux crossing the windings 3a to 4b.

Further, referring to FIG. 3, a magnetic flux that returns from the main core 1 to the main core 1 again via the bypass cores 2a and 2b (that is, a magnetic flux that passes through the bypass cores 2a and 2b) is generated. The magnetic flux passing through the bypass core 2a forms a closed loop through the inside and outside of the solenoid-like winding 3a and intersects the winding 3a, but this magnetic flux is substantially only inside the solenoid-like winding 4a. Reciprocates in, and thus does not form a closed loop through the inside and outside of the winding 4a and does not intersect the winding 4a. Similarly, the magnetic flux passing through the bypass core 2b forms a closed loop through the inside and outside of the solenoid-like winding 3b and intersects the winding 3b, but this magnetic flux is substantially the solenoid-like winding 4b. It reciprocates only inside the winding, and thus does not form a closed loop through the inside and outside of the winding 4b and does not intersect the winding 4b. By generating the magnetic flux passing through the bypass cores 2a and 2b, the leakage inductance of the transformer 10 can be increased as compared with the case without the bypass core. The smaller the distance B2 (see FIG. 1) between the main core 1 and the bypass cores 2a and 2b (that is, the thinner the spacer 6 in FIG. 1), the easier it is for magnetic flux to pass through the bypass cores 2a and 2b. Further, the amount of magnetic flux passing through the bypass cores 2a and 2b changes according to the length B4 of the bypass cores 2a and 2b (see FIG. 1). Specifically, as the area of the region where the main core 1 and the bypass cores 2a and 2b face each other increases, the amount of magnetic flux passing through the bypass cores 2a and 2b increases. Therefore, for example, the exciting inductance of the transformer 10 is adjusted by changing the distance B2 between the main core 1 and the bypass cores 2a and 2b and / or changing the lengths B4 of the bypass cores 2a and 2b. Can be done.

FIG. 4 is a front view schematically illustrating an example of the configuration of the transformer 100 according to the comparative example. FIG. 4 shows an example of a transformer provided with a general source of leakage flux according to the prior art. The transformer 100 of FIG. 4 includes a core 101, a primary winding 103, and a secondary winding 104, and the core 101 has a portion around which the primary winding 103 is wound and a portion around which the secondary winding 104 is wound. A gap G is provided between and. Leakage flux is generated in the gap G. In the transformer 100 of FIG. 4, the distance between the primary winding 103 and the secondary winding 104 is increased in order to increase the leakage inductance. Therefore, there is a limit to increasing the leakage inductance while maintaining the number of turns of the primary winding 103 and the secondary winding 104. Further, in the transformer 100 of FIG. 4, since the gap G is close to the primary winding 103 and the secondary winding 104, the leakage flux generated from the gap G intersects with the primary winding 103 or the secondary winding 104. Causes a loss.

On the other hand, in the transformer 10 according to the present embodiment, by generating the magnetic flux passing through the bypass cores 2a and 2b, it is possible to generate a larger leakage inductance than in the case without the bypass core. Further, in the transformer 10 according to the present embodiment, the exciting inductance can be adjusted by the gap G in the sections A3 and A4 of the main core 1. Here, since the gap G is formed at a position away from the windings 3a to 4b as described above, it is possible to prevent an increase in loss due to the leakage flux crossing the windings 3a to 4b.

Further, as shown in FIG. 3, the windings 3a and 4a are wound so as to be alternately arranged on the surface of the main core 1, and the windings 3b and 4b are arranged so as to be alternately arranged on the surface of the main core 1. It is wound around. As a result, in the transformer 10 according to the present embodiment, the "proximity effect" that occurs in the windings 3a to 4b can be reduced. Next, the reduction of the proximity effect will be described with reference to FIGS. 5 and 6.

FIG. 5 is a graph schematically illustrating an example of the operation of a transformer provided with windings 103 and 104 according to a comparative example. In the example of FIG. 5, the windings 103 and 104 are not wound so as to be alternately arranged on the surface of the core, but the winding 103 is continuously wound and wound over a predetermined section on the surface of the core. The case where the wire 104 is continuously wound over another predetermined section of the surface of the core is shown. The windings 103 and 104 are each wound on the surface of the core with a single layer and the number of turns M. The magnetomotive force is proportional to the current i flowing through the winding and the number of turns m. Therefore, as the number of turns m of the winding in which the current i flows in the same direction increases (m = 1, 2, ..., M), the magnetomotive force increases and the loss due to the proximity effect also increases.

FIG. 6 is a graph schematically illustrating an example of the operation of the transformer 10 of FIG. In FIG. 6, reference numeral “3” indicates winding 3a or 3b, and reference numeral “4” indicates winding 4a or 4b. As described above, one of the windings 3a and 4a alternately arranged on the surface of the main core 1 is used as the primary winding, and the other is used as the secondary winding. Similarly, one of the windings 3b and 4b alternately arranged on the surface of the main core 1 is used as the primary winding, and the other is used as the secondary winding. A current flows in the secondary winding in the direction opposite to the current flowing in the primary winding. Therefore, currents in opposite directions flow through the windings 3 and 4 alternately arranged on the surface of the main core 1. Therefore, according to the transformer 10 according to the present embodiment, by arranging the primary winding and the secondary winding alternately, the magnetomotive force is less likely to increase, and the winding is wound as shown in FIG. It is possible to reduce the loss due to the proximity effect as compared with the case of doing so.

Next, the connection of the windings 3a to 4b will be described with reference to FIGS. 7 to 12.

FIG. 7 is a diagram schematically illustrating an example of connection of windings 3a to 4b in the transformer 10 of FIG. 1. The end T2 of the winding 3a and the end T4 of the winding 3b are connected to each other. The end T6 of the winding 4a and the end T8 of the winding 4b are connected to each other. The end T1 of the winding 3a, the end T3 of the winding 3b, the end T5 of the winding 4a, and the end T7 of the winding 4b are used as input / output terminals of the transformer 10.

In the example of FIG. 7, the end portion T1 of the winding 3a is also referred to as a “first terminal”, the end portion T3 of the winding 3b is also referred to as a “second terminal”, and the end portion T5 of the winding 4a is referred to as a “second terminal”. It is also referred to as a "terminal of 3", and the end T7 of the winding 4b is also referred to as a "fourth terminal".

The windings 3a and 3b generate magnetic fluxes in the same direction along the loop of the main core 1 by the windings 3a and 3b when a current flows between the end T1 of the winding 3a and the end T3 of the winding 3b. As such, they are connected in series between the ends T1 and T3. The windings 4a and 4b generate magnetic fluxes in the same direction along the loop of the main core 1 by the windings 4a and 4b when a current flows between the end T5 of the winding 4a and the end T7 of the winding 4b. As such, they are connected in series between the ends T5 and T7. Therefore, when the windings 3a and 3b are used as the primary winding and the windings 4a and 4b are used as the secondary winding, the loop of the main core 1 when the input current I1 flows between the ends T1 and T3. The output current I2 flows between the ends T5 and T7 according to the change in the magnetic flux along the edge. Further, when the windings 4a and 4b are used as the primary winding and the windings 3a and 3b are used as the secondary winding, when the input current I2 flows between the ends T5 and T7, the loop of the main core 1 is used. The output current I1 flows between the ends T1 and T3 according to the change in the magnetic flux along the edge.

FIG. 8 is a circuit diagram schematically illustrating an example of a part of a power conversion device including the transformer 10 of FIG. 7. When the windings 3a and 3b are used as the primary winding and the windings 4a and 4b are used as the secondary winding, the diodes D1 to D4 are attached to the end T5 of the winding 4a and the end T7 of the winding 4b. A rectifier circuit including a diode bridge consisting of the same may be connected.

In the example of FIGS. 7 and 8, the number of turns of the windings 3a and 3b may be equal to or different from each other. Further, in the examples of FIGS. 7 and 8, the number of turns of the windings 4a and 4b may be equal to or different from each other.

FIG. 9 is a diagram schematically illustrating another example of the connection of the windings 3a to 4b in the transformer 10 of FIG. The end T2 of the winding 3a and the end T4 of the winding 3b are connected to each other. The end T6 of the winding 4a and the end T7 of the winding 4b are connected to each other. The end T1 of the winding 3a and the end T3 of the winding 3b are used as input terminals of the transformer 10, and the end T5 of the winding 4a and the end T8 of the winding 4b are the output terminals of the transformer 10. Used as. Further, the end portion T6 of the winding 4a and the end portion T7 of the winding 4b connected to each other are also used as output terminals of the transformer 10. In the example of FIG. 9, windings 3a and 3b are used as primary windings, and windings 4a and 4b are used as secondary windings.

In the example of FIG. 9, the end portion T1 of the winding 3a is also referred to as a “first terminal”, the end portion T3 of the winding 3b is also referred to as a “second terminal”, and the end portion T5 of the winding 4a is referred to as a “second terminal”. The end T8 of the winding 4b is also referred to as a "fourth terminal", and the end T6 of the winding 4a and the end T7 of the winding 4b connected to each other are referred to as a "fifth terminal". Also called.

The windings 3a and 3b generate magnetic fluxes in the same direction along the loop of the main core 1 by the windings 3a and 3b when a current flows between the end T1 of the winding 3a and the end T3 of the winding 3b. As such, they are connected in series between the ends T1 and T3. The windings 4a and 4b are connected when a current flows from the end T6 of the winding 4a to the end T5 and a current flows from the end T7 of the winding 4b to the end T8 (or the end T5 of the winding 4a). When a current flows from the end T6 and a current flows from the end T8 of the winding 4b to the end T7), the windings 4a and 4b generate magnetic fluxes in the same direction along the loop of the main core 1. Connected to each other. Therefore, when the input current I1 flows between the end T1 of the winding 3a and the end T3 of the winding 3b, the end T6 of the winding 4a responds to the change in the magnetic flux along the loop of the main core 1. The output current I2a flows through the portion T5, and the output current I2b flows from the end T7 of the winding 4b to the end T8 (or the output current I2a flows from the end T5 of the winding 4a to the end T6, and , The output current I2b flows from the end T8 of the winding 4b to the end T7).

FIG. 10 is a circuit diagram schematically illustrating an example of a part of a power conversion device including the transformer 10 of FIG. When the windings 4a and 4b have the same number of turns, the end T6 of the winding 4a and the end T7 of the winding 4b connected to each other become the center tap of the secondary winding. In this case, a rectifier circuit using a center tap including diodes D5 and D6 may be connected to the ends T5 to T8 of the windings 4a and 4b.

In the example of FIGS. 9 and 10, the number of turns of the windings 3a and 3b may be equal to or different from each other. Further, in the examples of FIGS. 9 and 10, the turns of the windings 4a and 4b are set to be equal to each other as described above.

FIG. 11 is a diagram schematically illustrating still another example of the connection of the windings 3a to 4b in the transformer 10 of FIG. 1. The end T2 of the winding 3a and the end T3 of the winding 3b are connected to each other. The end T6 of the winding 4a and the end T8 of the winding 4b are connected to each other. The end T5 of the winding 4a and the end T7 of the winding 4b are used as input terminals of the transformer 10, and the end T1 of the winding 3a and the end T4 of the winding 3b are the output terminals of the transformer 10. Used as. Further, the end portion T2 of the winding 3a and the end portion T3 of the winding 3b connected to each other are also used as output terminals of the transformer 10. In the example of FIG. 11, windings 4a and 4b are used as primary windings, and windings 3a and 3b are used as secondary windings.

In the example of FIG. 11, the end portion T1 of the winding 3a is also referred to as a “first terminal”, the end portion T4 of the winding 3b is also referred to as a “second terminal”, and the end portion T5 of the winding 4a is referred to as a “second terminal”. The end T7 of the winding 4b is also referred to as a "fourth terminal", and the end T2 of the winding 3a and the end T3 of the winding 3b connected to each other are referred to as a "fifth terminal". Also called.

The windings 3a and 3b are used when a current flows from the end T2 of the winding 3a to the end T1 and a current flows from the end T3 of the winding 3b to the end T4 (or the end T1 of the winding 3a). When a current flows from the end T2 and a current flows from the end T4 of the winding 3b to the end T3), the windings 3a and 3b generate magnetic fluxes in the same direction along the loop of the main core 1. Connected to each other. The windings 4a and 4b generate magnetic fluxes in the same direction along the loop of the main core 1 by the windings 4a and 4b when a current flows between the end T5 of the winding 4a and the end T7 of the winding 4b. As such, they are connected in series between the ends T5 and T7. Therefore, when the input current I2 flows between the end T5 of the winding 4a and the end T7 of the winding 4b, the end T2 of the winding 3a responds to the change in the magnetic flux along the loop of the main core 1. The output current I1a flows through the portion T1, and the output current I1b flows from the end T3 of the winding 3b to the end T4 (or the output current I1a flows from the end T1 of the winding 3a to the end T2, and , The output current I1b flows from the end T4 of the winding 3b to the end T3).

FIG. 12 is a circuit diagram schematically illustrating an example of a part of a power conversion device including the transformer 10 of FIG. When the number of turns of the windings 3a and 3b is equal to each other, the end T2 of the winding 3a and the end T3 of the winding 3b connected to each other become the center tap of the secondary winding. In this case, a rectifier circuit using a center tap including diodes D7 and D8 may be connected to the ends T1 to T4 of the windings 3a and 3b.

In the examples of FIGS. 11 and 12, the turns of the windings 3a and 3b are set to be equal to each other as described above. Further, in the examples of FIGS. 11 and 12, the number of turns of the windings 4a and 4b may be equal to or different from each other.

As described with reference to FIGS. 7 to 12, the transformer 10 according to the present embodiment is applicable to, for example, a power conversion device including a rectifier circuit including a diode bridge, and uses a center tap. It can also be applied to a power conversion device equipped with a diode.

[Effect of the first embodiment]
The transformer 10 according to the present embodiment can generate a large leakage inductance by generating a magnetic flux passing through the bypass cores 2a and 2b. Further, the transformer 10 according to the present embodiment prevents the leakage magnetic flux from intersecting the windings 3a to 4b by generating the leakage magnetic flux in the gap G formed at a position away from the windings 3a to 4b. However, the exciting inductance can be adjusted while preventing an increase in loss due to the leakage magnetic flux crossing the windings 3a to 4b. As described above, according to the transformer 10 according to the present embodiment, the leakage inductance can be increased without increasing the loss.

Further, in the transformer 10 according to the present embodiment, the amount of the leakage flux can be changed according to the distance of the gap G. Further, in the transformer 10 according to the present embodiment, the bypass cores 2a and 2b depend on the distance B2 between the main core 1 and the bypass cores 2a and 2b and / or the lengths of the bypass cores 2a and 2b. The amount of magnetic flux passing through the bypass cores 2a, 2b can be changed, and thus the leakage inductance generated by the magnetic flux passing through the bypass cores 2a, 2b can be changed.

Further, in the transformer 10 according to the present embodiment, by winding the primary winding and the secondary winding so as to be alternately arranged on the surface of the main core 1, the winding is performed as compared with the case where the primary winding is not wound in this way. The loss due to the proximity effect of the windings can be reduced.

Further, in the transformer 10 according to the present embodiment, the windings 3a to 4b are wound around the surface of the main core 1 so as to be in contact with the surface of the main core 1 (that is, in a single layer), so that the windings 3a to 4b cause the windings 3a to 4b. The heat generated can be dissipated well. A part of the windings 3a and 3b is sandwiched between the main core 1 and the bypass cores 2a and 2b, but this does not significantly hinder the heat dissipation of the windings 3a and 3b.

Further, in the transformer 10 according to the present embodiment, as described above, the windings 3a to 4b are wound in a single layer on the surface of the main core 1, but a plurality of sections A1 along the loop of the main core 1 Since the windings 3a to 4b are wound around A2, the number of windings 3a to 4b can be increased by effectively utilizing the surface of the main core 1.

Further, the transformer 10 according to the present embodiment can easily incorporate the bypass cores 2a and 2b due to its simple configuration.

Patent Document 1 does not consider the loss due to the leakage flux crossing the winding, and therefore cannot reduce the loss due to such leakage flux.

Further, in Patent Document 1, since the magnetic material gap piece is located between the primary winding and the secondary winding, the magnetic flux is shielded by the winding and it is difficult to pass through the magnetic material gap piece. Therefore, it is considered that the effect of increasing the leakage inductance is small even if the magnetic material gap piece is provided.

Further, according to Patent Document 1, the primary winding is wound around one side of an iron core having a rectangular loop shape, the secondary winding is wound around the primary winding, and the magnetic gap pieces are wound. It is inserted every predetermined angular width between the primary winding and the secondary winding. The length of the magnetic gap pieces is constrained to be less than or equal to the width of the primary and secondary windings. Therefore, in Patent Document 1, the length of the magnetic gap piece cannot be arbitrarily changed in order to change the amount of the leakage flux.

Further, according to Patent Document 1, as described above, the primary winding is wound around the iron core, the secondary winding is wound around the primary winding, and in each of the primary winding and the secondary winding. Proximity effect is expected to occur. In Patent Document 1, the loss due to the proximity effect cannot be reduced.

Further, in Patent Document 1, since the primary winding is wound around the iron core and the secondary winding is wound around the primary winding, it is difficult to dissipate the heat generated by the primary winding and the secondary winding. , It is thought that the temperature of the transformer tends to rise.

According to Patent Document 2, since the first winding and the second winding are wound around the middle leg of the first magnetic material, the positions of the first magnetic material away from the first winding and the second winding. Cannot form a gap in. Therefore, it is not possible to form a gap so that the leakage flux does not easily intersect the winding, and it is difficult to increase the leakage flux without increasing the loss.

Further, according to Patent Document 2, the first winding is wound around the first magnetic material, the second winding is wound around the first winding, and the first winding and the second winding are respectively. It is considered that a proximity effect occurs in. In Patent Document 2, the loss due to the proximity effect cannot be reduced.

Further, according to Patent Document 2, since the first winding is wound around the first magnetic material and the second winding is wound around the first winding, the first winding and the second winding are wound. It is considered that it is difficult to dissipate the heat generated by the transformer and the temperature of the transformer tends to rise.

On the other hand, in the transformer 10 according to the present embodiment, all of increasing the leakage inductance, preventing the increase in loss due to the leakage flux crossing the winding, and reducing the loss due to the proximity effect. Is to achieve. It is not easy to come up with a transformer that can meet all of these requirements.

[Modified example of the first embodiment]
Next, a modification of the first embodiment will be described with reference to FIGS. 13 to 22.

[First Modification Example of First Embodiment]
FIG. 13 is a front view schematically illustrating an example of the configuration of the transformer 10A according to the first modification of the first embodiment. The transformer 10A of FIG. 13 includes a main core 1A instead of the main core 1 of FIG. The main core 1A includes a plurality of main core portions 1Aa and 1Ab. In FIG. 1, the gap G in the section A3 and the gap G in the section A4 are shown at equidistant positions from the sections A1 and A2, but each gap G may be formed at any position in the sections A3 and A4. In the example of FIG. 13, the transformer 10A has one gap G formed in the section A3 closer to the section A1 than the section A2, and 1 formed in the section A4 closer to the section A2 than the section A1. It has two gaps G. The gap G intersects the loop of the main core 1A at a position away from both the sections A1 and A2 of the main core 1A so that the leakage flux generated in the gap G does not substantially intersect the windings 3a to 4b. If it is formed on the main core 1A, it may be formed at any position.

[Second variant of the first embodiment]
FIG. 14 is a front view schematically illustrating an example of the configuration of the transformer 10B according to the second modification of the first embodiment. The transformer 10B of FIG. 14 includes a main core 1B instead of the main core 1 of FIG. The main core 1B includes a plurality of main core portions 1Ba and 1Bb. The main core 1B includes one gap G formed in the section A3. The transformer according to the present embodiment may include only one gap depending on the amount of desired leakage flux. The main core 1B may include one gap G formed in the section A4 instead of the gap G formed in the section A3.

When the main core 1B has only one gap G, the main core 1B may be integrally formed instead of being composed of a plurality of main core portions.

[Third variant of the first embodiment]
FIG. 15 is a front view schematically illustrating an example of the configuration of the transformer 10C according to the third modification of the first embodiment. The transformer 10C of FIG. 15 includes a main core 1C instead of the main core 1 of FIG. The main core 1C includes a plurality of main core portions 1Ca, 1Cb, 1Cc. In the example of FIG. 15, the transformer 10C includes a plurality of gaps G formed in the section A3 and a plurality of gaps G formed in the section A4. The transformer according to the present embodiment has a plurality of gaps formed in the main core 1C so as to intersect the loop of the main core 1 C in at least one of the sections A3 and A4, depending on the amount of the desired leakage flux. It may be provided with G. If the distance between the gaps G is small, the leakage range of the leakage flux becomes small, and it becomes difficult to cross the winding.

A plurality of gaps G may be provided in one of the sections A3 and A4, and one gap G may be provided in the other of the sections A3 and A4. Further, one of the sections A3 and A4 may have a plurality of gaps G, and the other of the sections A3 and A4 may not have a gap G.

[Fourth variant of the first embodiment]
FIG. 16 is a front view schematically illustrating an example of the configuration of the transformer 10D according to the fourth modification of the first embodiment. In the transformer 10D of FIG. 16, the windings 3b and 4b and the bypass core 2b of FIG. 1 are removed. Further, the transformer 10D of FIG. 16 includes a main core 1D instead of the main core 1 of FIG. The main core 1D includes a plurality of main core portions 1Da and 1Db. The main core portion 1Da is formed, for example, in a U shape, and the main core portion 1Db is formed in an I shape, for example, in the same manner as in the main core portion 1a of FIG. The plurality of main core portions 1Da and 1Db are mechanically connected to each other so as to form at least one gap G between them. The main core 1D has the shape of a loop as a whole.

The transformer 10D of FIG. 16 can also generate a large leakage inductance by generating a magnetic flux passing through the bypass core 2a, similarly to the transformer 10 of FIG. Further, in the transformer 10D of FIG. 16, similarly to the transformer 10 of FIG. 1, the leakage magnetic flux is wound by generating the leakage magnetic flux in the gap G formed at a position away from the windings 3a and 4a. The exciting inductance can be adjusted while preventing the leakage flux from intersecting the windings 3a and 4a and preventing the increase in loss due to the leakage magnetic flux intersecting the windings 3a and 4a. Thus, according to the transformer 10D of FIG. 16, the leakage inductance can be increased without increasing the loss.

Further, the transformer 10D of FIG. 16 can also change the amount of the leakage flux according to the distance of the gap G, similarly to the transformer 10 of FIG. Also, the transformer 10D of FIG. 16, like the transformer 10 of FIG. 1, also has a bypass core depending on the distance between the main core 1D and the bypass core 2a and / or according to the length of the bypass core 2a. The amount of magnetic flux passing through 2a can be varied and thus the leakage inductance generated by the magnetic flux passing through the bypass core 2a can be varied.

Further, the transformer 10D of FIG. 16 is also wound so that the primary winding and the secondary winding are alternately arranged on the surface of the main core 1D , similarly to the transformer 10 of FIG. It is possible to reduce the loss due to the proximity effect of the windings as compared with the case where the winding is not performed in this way.

Further, the transformer 10D of FIG. 16 is also wound so that the windings 3a and 4a are in contact with the surface of the main core 1D every turn (that is, in a single layer), similarly to the transformer 10 of FIG. Therefore, the heat generated by the windings 3a and 4a can be satisfactorily dissipated.

Further, the transformer 10D of FIG. 16 can also easily incorporate the bypass core 2a due to its simple configuration, similar to the transformer 10 of FIG.

[Fifth variant of the first embodiment]
FIG. 17 is a side view schematically illustrating an example of the configuration of the transformer 10E according to the fifth modification of the first embodiment. FIG. 18 is a top view schematically illustrating an example of the configuration of the transformer 10E of FIG. The transformer 10E of FIG. 17 includes bypass cores 2a1 and 2b2 in place of the bypass cores 2a and 2b of FIG.

The bypass cores 2a1 and 2a2 are provided along the section of the main core 1 around which the winding 3a is wound and outside the winding 3a. The bypass cores 2b1 and 2b2 are provided along the section of the main core 1 around which the winding 3b is wound and outside the winding 3b. The winding 4a is wound around the main core 1 and the bypass cores 2a1 and 2a2 in the section of the main core 1 around which the winding 3a is wound. The winding 4b is wound around the main core 1 and the bypass cores 2b1 and 2b2 in the section of the main core 1 around which the winding 3b is wound.

In the example of FIG. 18, the bypass cores 2a1 and 2a2 are also referred to as a "first bypass core", and the bypass cores 2b1 and 2b2 are also referred to as a "second bypass core".

The transformer 10E of FIG. 17 includes two bypass cores 2a1 and 2a2 in relation to windings 3a and 4a and two bypass cores 2b1 and 2b2 in relation to windings 3b and 4b. As a result, the amount of magnetic flux passing through the bypass cores 2a1, 2a2 , 2b1, 2b2 can be increased as compared with the case where the bypass cores 2a and 2b are provided one by one as shown in FIG.

Three or more bypass cores may be provided in relation to the windings 3a, 4a, and three or more bypass cores may be provided in relation to the windings 3b, 4b.

[Sixth modification of the first embodiment]
FIG. 19 is a front view schematically illustrating an example of the configuration of the transformer 10F according to the sixth modification of the first embodiment. The transformer 10F of FIG. 19 includes bypass cores 2Fa and 2Fb in place of the bypass cores 2a and 2b of FIG.

The bypass cores 2Fa and 2Fb extend along the main core 1 and bend toward the main core 1 at both ends.

In the example of FIG. 19, the bypass core 2Fa is also referred to as a “first bypass core”, and the bypass core 2Fb is also referred to as a “second bypass core”.

If the distance between the main core and the bypass core is not sufficiently small, magnetic flux passing through the bypass cores 2Fa and 2Fb is unlikely to occur. According to the transformer 10F of FIG. 19, the distance between the main core 1 and the bypass cores 2Fa and 2Fb is shortened by bending both ends of the bypass cores 2Fa and 2Fb. As a result, the magnetic flux can easily pass through the bypass cores 2Fa and 2Fb as compared with the case of the transformer 10 of FIG. 1, and the amount of the magnetic flux passing through the bypass cores 2Fa and 2Fb can be increased. Therefore, the leakage inductance can be increased as compared with the case of the transformer 10 of FIG.

[7th modification of the 1st embodiment]
FIG. 20 is a front view schematically illustrating an example of the configuration of the transformer 10G according to the seventh modification of the first embodiment. The transformer 10G of FIG. 20 includes bypass cores 2Ga and 2Gb in place of the bypass cores 2a and 2b of FIG.

The bypass cores 2Ga and 2Gb extend along the main core 1 and bend along the main core 1 at both ends.

In the example of FIG. 20, the bypass core 2Ga is also referred to as a “first bypass core”, and the bypass core 2Gb is also referred to as a “second bypass core”.

As described above, as the area of the region where the main core and the bypass core face each other increases, the amount of magnetic flux passing through the bypass cores 2Ga and 2Gb increases. According to the transformer 20G of FIG. 20, by bending both ends of the bypass cores 2Ga and 2Gb, the area of the region where the main core 1 and the bypass cores 2Ga and 2Gb face each other increases. As a result, the magnetic flux can easily pass through the bypass cores 2Ga and 2Gb as compared with the case of the transformer 10 of FIG. 1, and the amount of the magnetic flux passing through the bypass cores 2Ga and 2Gb can be increased. Therefore, the leakage inductance can be increased as compared with the case of the transformer 10 of FIG.

[Eighth variant of the first embodiment]
FIG. 21 is a side view schematically illustrating an example of the configuration of the transformer 10H according to the eighth modification of the first embodiment. FIG. 22 is a top view schematically illustrating an example of the configuration of the transformer 10H of FIG. 21. The transformer 10H of FIG. 21 includes bypass cores 2Ha1 and 2Hb2 in place of the bypass cores 2a and 2b of FIG. The transformer 10H corresponds to a combination of the fifth modification and the seventh modification.

The bypass cores 2Ha1 and 2Ha2 are provided along the section of the main core 1 around which the winding wire 3a is wound and outside the winding wire 3a. The bypass cores 2Hb1 and 2Hb2 are provided along the section of the main core 1 around which the winding 3b is wound and outside the winding 3b. The winding 4a is wound around the main core 1 and the bypass cores 2Ha1 and 2Ha2 in the section of the main core 1 around which the winding 3a is wound. The winding 4b is wound around the main core 1 and the bypass cores 2Hb1 and 2Hb2 in the section of the main core 1 around which the winding 3b is wound. The bypass cores 2Ha1 and 2Hb2 extend along the main core 1 and bend along the main core 1 at both ends.

As shown in FIG. 21, the bypass cores 2Ha1 and 2Ha2 may be in contact with each other at both ends thereof. Similarly, the bypass cores 2Hb1 and 2Hb2 may touch each other at both ends thereof.

In the example of FIG. 21, the bypass cores 2Ha1 and 2Ha2 are also referred to as "first bypass cores", and the bypass cores 2Hb1 and 2Hb2 are also referred to as "second bypass cores".

According to the transformer 20H of FIG. 21, the leakage inductance can be increased as compared with the case of the transformer 10E of FIG. 17 and as compared with the case of the transformer 10G of FIG.

[Second Embodiment]
The power conversion device according to the second embodiment will be described with reference to FIGS. 23 to 24.

[Structure example of the second embodiment]
FIG. 23 is a circuit diagram schematically illustrating an example of the power conversion device according to the second embodiment. The power conversion device of FIG. 23 shows an example of a current resonance type DC-DC converter. The power conversion device of FIG. 23 includes a transformer 10, a DC power supply 21, a drive circuit 22, a load 23, capacitors C1 and C2, diodes D5 and D6, and switch elements Q1 and Q2.

The DC power supply 21 supplies a DC input voltage Vin. The switch elements Q1 and Q2 operate under the control of the drive circuit 22. The transformer 10 of FIG. 23 is configured in the same manner as the transformer 10 of FIG. 1, for example. The transformer 10 equivalently includes the inductors Lr and Lm. The inductors Lr and Lm and the capacitor C1 form a resonance circuit. The transformer 10 is connected to a rectifier circuit utilizing a center tap, which includes diodes D5 and D6, as described with reference to FIGS. 9 and 10. The rectified voltage is smoothed by the capacitor C2, and the smoothed output voltage Vout and output current Iout are supplied to the load 23.

FIG. 24 is a graph schematically illustrating an example of the operation of the resonance circuit of the power conversion device of FIG. 23. The graph of FIG. 24 shows the frequency characteristics of the resonant circuit including the inductor Lr, Lm and the capacitor C1 of FIG. 23, and shows the frequency characteristics when the inductance of the inductor Lr is small and large. In the power conversion device of FIG. 23, the gain of the resonance circuit is increased by lowering the switching frequency of the switch elements Q1 and Q2. By this control method, it is possible to deal with the fluctuation of the input voltage Vin and also to deal with the fluctuation of the load 23. However, according to FIG. 24, it can be seen that by adjusting the inductance of the inductor Lr, the maximum gain of the resonant circuit increases without changing the switching frequency. At the frequency f1, the gain when the inductance of the inductor Lr is large is higher than the gain when the inductance of the inductor Lr is small. On the other hand, at the frequency f2, the gain when the inductance of the inductor Lr is small is higher than the gain when the inductance of the inductor Lr is large. This makes it possible to achieve a wide range of input voltage and load without significantly increasing or decreasing the switching frequency.

According to the transformer 10 according to the embodiment of the present disclosure, the leakage inductance of the transformer 10 acts as the inductor Lr. Therefore, in the power conversion device of FIG. 23, the inductance of the resonant circuit can be adjusted without adding the component of the inductor Lr. By eliminating the need for an additional inductor Lr, the power density of the power converter can be increased.

According to the power conversion device according to the present embodiment, by providing the transformer 10, the exciting inductance can be adjusted without increasing the loss of the transformer 10, and the leakage inductance of the transformer 10 is increased. be able to. Further, the leakage inductance of the transformer 10 resonates, so that the gain of the power converter can be increased. Therefore, according to the present embodiment, it is possible to realize a power conversion device having a high power density.

In the power conversion device according to the present embodiment, the transformers 10A to 10H according to other modifications may be used instead of the transformer 10 in FIG.

According to the embodiment of the present disclosure, not only the circuit shown in FIG. 23 but also other power conversion devices including a transformer may be provided.

According to the embodiment of the present disclosure, not only the power conversion device but also other electronic circuits including a transformer may be provided.

[Other variants]
Although the embodiments of the present disclosure have been described in detail above, the above description is merely an example of the present disclosure in all respects. Needless to say, various improvements and modifications can be made without departing from the scope of the present disclosure. For example, the following changes can be made. In the following, the same reference numerals will be used for the same components as those in the above embodiment, and the same points as in the above embodiment will be omitted as appropriate.

Each of the above-described embodiments and modifications may be arbitrarily combined.

The embodiments described herein are merely exemplary of the present disclosure in all respects. Needless to say, various improvements and modifications can be made without departing from the scope of the present disclosure. That is, in carrying out the present disclosure, a specific configuration according to the embodiment may be appropriately adopted.

In FIG. 1 and others, a rectangular main core is shown, but the present invention is not limited to this. The main core may have a shape other than a rectangle, for example, a ring shape.

In FIG. 1 and others, the case where the main core consists of two main core portions has been described, but the present invention is not limited to this. The main core may be composed of three or more main core portions.

In FIG. 1 and others, the case where the windings 3a to 4b are wound around the two sections A1 and A2 has been described, but the present invention is not limited to this. The windings 3a to 4b may be wound around the main core in three or more separate sections of the loop of the main core, and as shown in FIG. 16, they are wound around the main core in one section. You may. Depending on the number of sections around which the windings 3a to 4b are wound, three or more bypass cores may be provided, or as shown in FIG. 16, one bypass core may be provided.

The shape and number of the bypass cores are shown in FIGS. 1, 17 to 22, etc., if a magnetic flux that returns from the main core to the main core via the bypass core (that is, a magnetic flux that passes through the bypass core) is generated. It is not limited to, and may be any other shape and number.

[summary]
The transformer and the power conversion device according to each aspect of the present disclosure may be expressed as follows.

The transformer (10, 10A to 10H) according to the first aspect of the present disclosure is
The main core (1,1A-1C) having the shape of a loop,
The first winding (3a) wound around the main core (1,1A to 1C) in the first section (A1) of the loop of the main core (1,1A to 1C).
The second section (A2) away from the first section (A1) of the loop of the main core (1,1A to 1C) is wound around the main core (1,1A to 1C). 2 windings (3b) and
At least one first bypass core (2a) provided along the first section (A1) of the main core (1,1A-1C) and outside the first winding (3a). )When,
A third winding wound around the main core (1,1A-1C) and the first bypass core (2a) in the first section (A1) of the main core (1,1A to 1C). (4a) and
At least one second bypass core (2b) provided along the second section (A2) of the main core (1,1A-1C) and outside the second winding (3b). )When,
A fourth winding wound around the main core (1,1A-1C) and the second bypass core (2b) in the second section (A2) of the main core (1,1A-1C). (4b) and
The main core (1,1A-1C) so as to intersect the loop of the main core (1,1A-1C) at a position away from both the first and second sections (A1, A2) of the main core (1,1A-1C). It comprises at least one gap (G) formed in the core (1,1A-1C).

According to the transformer (10, 10A to 10H) according to the second aspect of the present disclosure, in the transformer according to the first aspect,
The first bypass core (2a) extends over a length exceeding the length of the first section (A1).
The second bypass core (2b) extends over a length that exceeds the length of the second section (A2).

According to the transformer (10, 10A to 10H) according to the third aspect of the present disclosure, in the transformer according to the second aspect,
The first and second bypass cores (2a, 2b) extend along the main core (1,1A-1C) and at both ends towards or above the main core (1,1A-1C). It bends along the main core (1,1A-1C).

The transformer (10, 10A to 10H) according to the fourth aspect of the present disclosure is the transformer according to one of the first to third aspects.
A plurality of first bypass cores (2a1,2a2; 2Ha1,2Ha2) and a plurality of second bypass cores (2b1,2b2; 2Hb1,2Hb2) are provided.

According to the transformer (10, 10A to 10H) according to the fifth aspect of the present disclosure, in the transformer according to one of the first to fourth aspects,
The first and third windings (3a, 4a) are in contact with the surface of the main core (1,1A to 1C) every turn, and the main core (1,1A to 1C), respectively. Wrapped so that they are alternately placed on the surface of the
The second and fourth windings (3b, 4b) are in contact with the surface of the main core (1,1A to 1C) every turn, and the main core (1,1A to 1C), respectively. It is wound so as to be alternately arranged on the surface of the.

The transformer (10, 10A to 10H) according to the sixth aspect of the present disclosure is the transformer according to one of the first to fifth aspects.
In the third section (A3) between one end of the first section (A1) and one end of the second section (A2) in the loop of the main core (1,1A to 1C). With at least one gap (G) formed in the main core (1,1A-1C) so as to intersect the loop of the main core (1,1A-1C).
In the fourth section (A4) between the other end of the first section (A1) and the other end of the second section (A2) in the loop of the main core (1,1A to 1C). , With at least one gap (G) formed in the main core (1,1A-1C) so as to intersect the loop of the main core (1,1A-1C).

The transformer (10, 10A to 10H) according to the seventh aspect of the present disclosure is the transformer according to the sixth aspect.
A plurality of gaps (G) formed in the main core (1C) so as to intersect the loop of the main core (1C) in at least one of the third and fourth sections (A3, A4). Be prepared.

The transformer (10, 10A to 10H) according to the eighth aspect of the present disclosure is the transformer according to one aspect of the first to seventh aspects.
The transformer has first to fourth terminals and has
The first and second windings (3a, 3b) are the main core by the first and second windings (3a, 3b) when a current flows between the first and second terminals. It is connected in series between the first and second terminals so as to generate magnetic fluxes in the same direction along the loop (1,1A to 1C).
The third and fourth windings (4a, 4b) are the main core by the third and fourth windings (4a, 4b) when a current flows between the third and fourth terminals. It is connected in series between the third and fourth terminals so as to generate magnetic fluxes in the same direction along the loop (1, 1A to 1C).

The transformer (10, 10A to 10H) according to the ninth aspect of the present disclosure is the transformer according to one of the first to seventh aspects.
The transformer has first to fifth terminals and has
The first and second windings (3a, 3b) are the main core by the first and second windings (3a, 3b) when a current flows between the first and second terminals. It is connected in series between the first and second terminals so as to generate magnetic fluxes in the same direction along the loop (1,1A to 1C).
The third winding (4a) is connected between the third and fifth terminals.
The fourth winding (4b) is connected between the fourth and fifth terminals.
The third and fourth windings (4a, 4b) are the third and fourth windings (4a, 4b) when a current flows from the fifth terminal to the third and fourth terminals, respectively. ) Are connected to each other so as to generate magnetic fluxes in the same direction along the loop of the main core (1,1A to 1C).

The transformer (10, 10A to 10H) according to the tenth aspect of the present disclosure is the transformer according to one of the first to seventh aspects.
The transformer has first to fifth terminals and has
The first winding (3a) is connected between the first and fifth terminals.
The second winding (3b) is connected between the second and fifth terminals.
The first and second windings (3a, 3b) are the first and second windings (3a, 3b) when a current flows from the fifth terminal to the first and second terminals, respectively. ) Connected to each other so as to generate magnetic fluxes in the same direction along the loop of the main core (1,1A to 1C).
The third and fourth windings (4a, 4b) are the main core by the third and fourth windings (4a, 4b) when a current flows between the third and fourth terminals. It is connected in series between the third and fourth terminals so as to generate magnetic fluxes in the same direction along the loop (1, 1A to 1C).

The power conversion device according to the eleventh aspect of the present disclosure includes a transformer (10, 10A to 10H) according to one aspect of the first to tenth aspects.

The transformer according to each aspect of the present disclosure is applicable to, for example, a power conversion device having a high power density.

1,1A-1D ... Main core,
1a, 1b, 1Aa to 1Da, 1Ab to 1Db, 1Cc ... Main core part,
2a, 2b, 2a1-2b2, 2Fa, 2Fb, 2Ga, 2Gb, 2Ha1-2Hb2 ... Bypass core,
3a, 3b, 4a, 4b ... Winding,
5, 6 ... Spacer,
10,10A-10H ... Transformer,
21 ... DC power supply,
22 ... Drive circuit,
23 ... Load,
C1, C2 ... Capacitor,
D1 to D8 ... Diode,
G ... Gap,
Q1, Q2 ... Switch element.

Claims (11)

The main core with the shape of a loop and
With the first winding wound around the main core in the first section of the loop of the main core,
A second winding wound around the main core in a second section of the loop of the main core away from the first section,
With at least one first bypass core provided along the first section of the main core and outside the first winding.
A third winding wound around the main core and the first bypass core in the first section of the main core.
With at least one second bypass core provided along the second section of the main core and outside the second winding.
A fourth winding wound around the main core and the second bypass core in the second section of the main core.
It comprises at least one gap formed in the main core so as to intersect the loop of the main core at a position away from both the first and second sections of the main core.
Transformer. The first bypass core extends over a length that exceeds the length of the first section.
The second bypass core extends over a length that exceeds the length of the second section.
The transformer according to claim 1. The first and second bypass cores extend along the main core and bend towards or along the main core at both ends.
The transformer according to claim 2. A plurality of first bypass cores and a plurality of second bypass cores.
The transformer according to any one of claims 1 to 3. The first and third windings are wound so as to be in contact with the surface of the main core and alternately arranged on the surface of the main core every turn.
The second and fourth windings were wound so as to be in contact with the surface of the main core and to be alternately arranged on the surface of the main core every turn.
The transformer according to any one of claims 1 to 4. In the third section between one end of the first section and one end of the second section of the loop of the main core, the main core is formed so as to intersect the loop of the main core. With at least one gap,
Formed on the main core so as to intersect the loop of the main core in the fourth section between the other end of the first section and the other end of the second section of the loop of the main core. With at least one gap made,
The transformer according to any one of claims 1 to 5. At least one of the third and fourth sections comprises a plurality of gaps formed in the main core so as to intersect the loop of the main core.
The transformer according to claim 6. The transformer has first to fourth terminals and has
The first and second windings exert a magnetic flux in the same direction along the loop of the main core by the first and second windings when a current flows between the first and second terminals. Connected in series between the first and second terminals so as to occur
The third and fourth windings exert a magnetic flux in the same direction along the loop of the main core by the third and fourth windings when a current flows between the third and fourth terminals. Connected in series between the third and fourth terminals so as to occur.
The transformer according to any one of claims 1 to 7. The transformer has first to fifth terminals and has
The first and second windings exert a magnetic flux in the same direction along the loop of the main core by the first and second windings when a current flows between the first and second terminals. Connected in series between the first and second terminals so as to occur
The third winding is connected between the third and fifth terminals.
The fourth winding is connected between the fourth and fifth terminals.
The third and fourth windings are along the loop of the main core by the third and fourth windings as current flows from the fifth terminal to the third and fourth terminals, respectively. Connected to each other to generate magnetic fluxes in the same direction,
The transformer according to any one of claims 1 to 7. The transformer has first to fifth terminals and has
The first winding is connected between the first and fifth terminals.
The second winding is connected between the second and fifth terminals.
The first and second windings are along the loop of the main core by the first and second windings as current flows from the fifth terminal to the first and second terminals, respectively. Connected to each other to generate magnetic flux in the same direction,
The third and fourth windings exert a magnetic flux in the same direction along the loop of the main core by the third and fourth windings when a current flows between the third and fourth terminals. Connected in series between the third and fourth terminals so as to occur.
The transformer according to any one of claims 1 to 7. The transformer according to any one of claims 1 to 10 is provided.
Power converter.

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